Research On Ranging Communication Composite Signal Design And Processing Based On Pseudo-noise Codes

In many wireless application scenarios,ranging positioning and information transmission are essential functions,which are usually accomplished in independent ranging channels and communication channels.With the increase of communications traffic and functions,the limited spectrum resources are increasingly strained.In this case,it is of great significance to simultaneously realize ranging and communication functions over the same frequency spectrum,which can be effectively achieved by designing a ranging communication composite signal.The composite signal can be used in a system to achieve the two functions simultaneously,which improves the utilization of spectrum resources and reduces the complexity and overall consumption of the system to a certain extent.This thesis mainly studies the design method of the ranging communication composite signal and discusses the processing method of the composite signal in two different application scenarios.The specific work contents are as follows.Firstly,this thesis proposes a bit-level composite signal that superimposes ranging codes and sparsified coded codewords.In this composite method,through a mapping scheme designed by low-weight codewords or sequences,the information sequence is converted to a sparse sequence which is then superimposed on the ranging code.Then,a composite system of ranging and communication is designed based on the composite signal,and its promising application prospect in deep space communications is investigated preliminarily.For ranging,due to the small proportion of chip “1” in the sparse sequence,the chip flip rate of the ranging code is low,thereby retaining the good correlation characteristics of the ranging code component to complete the ranging function.For communications,the sparse sequence can be extracted without interference by eliminating the ranging code component.Simulation results show that the proposed scheme can support communication functions simultaneously with limited sacrifice of ranging performance without adding any additional resources,such as frequency and power.The performance loss of ranging can be controlled by adjusting the density of sparse sequences.Secondly,based on the proposed bit-level composite signal design method,a multi-base station cooperative positioning communication composite system is designed and the characteristics of the composite signal in the single input multiple output(SIMO)transmission model are discussed.On the one hand,the time delay from the ranging code component to each base station can be used to realize the localization of the target.On the other hand,the synchronization and diversity combination of multiple signals can be achieved by utilizing the characteristics of the composite signal.The simulation results show that the proposed composite system effectively improves the information transmission reliability through the macrodiversity receiving method,and simultaneously realizes the localization of the target.